The Blu-ray system has effectively improved the capacity of optical storage device in recent years. However, due to the limiting barrier of diffraction, Blu-ray system must use independent lens system from the DVD and CD systems to co-exist in an optical storage device. In addition, because of the requirements of accessing and recording of the optical storage device, the lens must follow with high sensitivity to match the errors caused by the manufacturing and rotation of the disc. In general, multi-axes voice coil motor (VCM) is used as the actuator for executing the above operation. FIG. 1 shows a schematic view of a conventional actuator. As shown in FIG. 1, coils 11 are sheathed outside of magnets 12. When currents run through coils 11, the interaction between coils 11 and magnets 12 will induce a Z-direction magnetic force to move object lens 14 carried by object lens holder 16 for focusing movement. The direction of focusing movement is the optical axis parallel to object lens 14. When the currents run through coil 15, the interaction between coil 15 and magnets 12, coil 15 will induce a Y-direction magnetic force to move object lens 14 carried by object lens holder 16 for tracking movement. The direction of tracking movement is the optical axis perpendicular to object lens 14.